Both entanglement and chaos theory have emerged as increasingly instrumental in many research areas. Entanglement is used to explain how two or more systems can share an instantaneous and correlated relationship that ignores physical distances. In one formulation, entanglement is said to have occurred when a composite system cannot be written as a product of the states of its component systems. Chaotic behavior, meanwhile, is generally attributed to a system's sensitive dependence on initial conditions and is characterized by its maximal Lyapunov exponent. In particular, the dense set of UPOs that chaotic systems typically admit on an attractor contains a rich source of qualitative information about the dynamical system and numerous control schemes have been designed to extract and stabilize these orbits. It has been said that UPOs constitute “the skeleton of classical and quantum chaos.”